Dental bridge

ABSTRACT

A system for attaching a natural tooth to a dental implant. The system comprises a dental prosthesis and an elastomeric cushion. The dental prosthesis has a first end and a second end. The first end is fixed to a natural tooth and the second end is engaged with a dental implant. The elastomeric cushion is positioned in contact, either directly or indirectly, with at least a portion of the dental implant and at least a portion of the dental prosthesis such that the elastomeric cushion permits movement of the second end relative to the dental implant in response to movement of the natural tooth transferred through the dental prosthesis to the second end.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and is a divisional of U.S. patentapplication Ser. No. 12/245,434, filed on Oct. 3, 2008, which isincorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to the field of dentistry, and is morespecifically directed to a dental bridge system that may be securedbetween a natural tooth and an implant in such a manner so as to permitlimited movement of the natural tooth and implant relative to oneanother.

2. Description of Related Art

Many patients require dental restorations or prostheses or a combinationof dental restorations and prostheses to restore function or foraesthetic reasons. Some common dental restorations and prosthesesinclude inlays, onlays, veneers, implants, crowns, bridges, anddentures. Depending on the patient's need, the dental restorations andprostheses can be removable or fixed. Dental restorations or dentalprostheses provide the appearance of teeth and are constructed to mimicthe function of teeth, such as masticating food and allowing for properspeech patterns.

One type of fixed or permanent dental restoration is an implant.Implants can replace an individual tooth or a combination of teeth andcan support a crown, a bridge, or a denture. The implant functions as anartificial tooth root. The most common type of implant is secured in thebony tissue of the upper or lower jaw. Implants can also be secured ontop of the jaw bone under the periosteum. Implants secured in the bonytissue of the upper or lower jaw are generally made out of titanium,titanium alloy, or some other medically compatible metal. A portion ofthe implant is screwed or tapped into a surgically prepared site in thebony tissue of the upper or lower jaw. The portion of the implant leftexposed above the gumline can support a prosthesis such as a crown, abridge, or a denture. Once the implant is in place, a process calledosseointegration occurs. Osseointegration is when the bony tissue growsaround the portion of the implant inserted in the jaw such that there isa structural and functional connection between the living bony tissueand the surface of the dental implant. After osseointegration hasoccurred, the portion of the implant inserted into the jaw is rigidlyfixed in place by the bony tissue. The prosthesis can either be more orless permanently fixed to the implant or can be secured such that it isregularly removable.

Another type of dental restoration is a bridge. Bridges can be used toreduce the risk of gum disease, correct certain bite issues, improvespeech, and replace missing teeth. Dental bridges are generally made upof at least two crowns. Crowns, also known as dental caps or tooth caps,are designed to cap the portion of a natural tooth at and above thegumline. Crowns essentially become the new visible portion of the tooththat can be used for chewing and allow for proper speech patterns.Crowns can also be made to fit over the portion of a dental implant leftexposed above the gumline as described above. Crowns are generally madeout of porcelain or dental ceramic, metal such as gold or other metalalloy, or a combination of porcelain and metal. Typically, dentalbridges also have at least one artificial tooth, or pontic, fusedbetween the two dental crowns.

Bridges containing pontics are a useful dental restoration option whenmultiple implants to restore multiple teeth cannot be used due tocertain anatomical limitations or as a more cost effective treatmentoption. For example, when a patient loses a tooth in the lower jaw andthe use of an implant would require inserting the implant in the lowerjaw near the inferior alveolar nerve, there is a risk that inserting theimplant could injure the nerve. If the missing tooth location is betweentwo natural teeth or is between two dental implants, then a traditionaldental bridge having a pontic can be used to restore the patient'smissing teeth.

Another example of how bridges can be a particularly useful method ofrestoration is when the patient loses a tooth in the upper jaw below asinus. As the bone where the missing tooth deteriorates through non-use,the sinus cavity expands into the space left by the bone, creating apneumatized sinus. Normally, inserting an implant where there is apneumatized sinus requires a sinus grafting procedure where the floor ofthe sinus is lifted by placing a bone graft, thereby creating adequatebony tissue to support the implant. This procedure is expensive andrequires a six to twelve month recovery period. If the missing toothspace has a natural tooth on each side or a dental implant on each side,then a traditional dental bridge having a pontic can be used instead ofan implant, thereby avoiding the sinus grafting procedure.

A traditional dental bridge cannot be anchored to both a natural toothand an implant without significant risk. This is because natural teethand dental implants respond differently to occlusal or compressiveforces. The root of a natural tooth rests in a socket in the bony tissueof the jaw where it is attached and cushioned with periodontal ligamentfibers. These fibers allow the natural tooth to move slightly inresponse to occlusal forces. The space between the tooth root and a wallof the bony tissue socket is roughly 0.25 mm. Normal, healthyphysiologic lateral tooth mobility can range from less than 0.25 mm tomore than 1 mm. After osseointegration, a dental implant is rigidrelative to the bony tissue and cannot move in response to occlusalforces. A bridge anchored to a natural tooth on one side and to a dentalimplant on the other side is subjected to non-uniform stress duringchewing and biting. This non-uniform stress can cause a structuralfailure on either end of the bridge.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a dental bridge system that may besecured between a natural tooth and a dental implant. The systemcomprises a dental prosthesis and an elastomeric cushion. The dentalprosthesis connects a natural tooth and a dental implant. Theelastomeric cushion is positioned so that it is in contact, eitherdirectly or indirectly, with at least a portion of the dental prosthesisand at least a portion of the dental implant so as to permit movement ofthe dental prosthesis relative to the dental implant. As the end of thedental prosthesis that is fixed to the natural tooth moves in responseto movement of the natural tooth, the end of the dental prosthesisengaging the dental implant moves against the elastomeric cushion eventhough the dental implant remains rigid.

It is believed that this system will be particularly effective inallowing dental bridges to be more or less permanently installed betweena natural tooth and a dental implant with much less risk of structuraldamage to all members of the system. The elastomeric cushion allows theend of the prosthesis engaging the dental implant to move in a way thatmimics the way the end of the prosthesis fixed to the natural toothmoves in response to the natural tooth movement permitted by theperiodontal ligament fibers. To do this, the elastomeric cushion must bemanufactured from a material that is sufficiently durable and yet iselastic enough to allow the appropriate amount of movement.

In one embodiment, the system comprises a dental prosthesis having a keyformed at one end, a corresponding notch formed in a dental implantcrown, and an elastomeric cushion positioned at the interface of the keyand the notch. The key is configured to securely fit within the notch soas to connect the prosthesis to the implant. The elastomeric cushion ispositioned at the interface of the key and notch so as to permitmovement of the prosthesis relative to the implant.

In an alternative embodiment the system comprises a dental prosthesishaving a key formed at one end, a pocket extending outwardly from thedental implant crown, and an elastomeric cushion positioned at theinterface of the key and the pocket. The key is configured to bereceived within the pocket so as to connect the prosthesis to theimplant. The elastomeric cushion is positioned within the pocket at theinterface of the key and pocket surfaces so as to permit movement of theprosthesis relative to the implant.

In another embodiment, the system comprises a dental prosthesis, havinga first end configured to receive a natural tooth and a second endconfigured to receive the exposed portion of the dental implant, and anelastomeric cushion at the interface of the dental implant and thedental prosthesis. When positioned in place, the prosthesis connects thenatural tooth to the implant. The elastomeric cushion fixed at theinterface of the prosthesis and the implant enables the prosthesis tomove with respect to the implant.

Additional aspects of the invention, together with the advantages andnovel features appurtenant thereto, will be set forth in part in thedescription which follows, and in part will become apparent to thoseskilled in the art upon examination of the following, or may be learnedfrom the practice of the invention. The objects and advantages of theinvention may be realized and attained by means of the instrumentalitiesand combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view, taken along line 1 of FIG. 2, of adental restoration having a dental bridge system in accordance with afirst embodiment of the present invention.

FIG. 2 is a top view of the dental bridge system of FIG. 1.

FIG. 3 is an exploded, side view of the dental restoration having thedental bridge system of FIG. 1 wherein the elastomeric cushion is fixedto the notch.

FIG. 4 is an exploded, side view of the dental restoration having thedental bridge system of FIG. 1 wherein the elastomeric cushion is fixedto the key.

FIG. 5 is a cross-sectional view of a dental restoration having a dentalbridge system in accordance with a second embodiment of the presentinvention.

FIG. 6 is an exploded, side view of the dental restoration having thedental bridge system of FIG. 5.

FIG. 7 is a cross-sectional view of a dental restoration having a dentalbridge system in accordance with a third embodiment of the presentinvention.

FIG. 8 is an exploded, side view of the dental restoration having thedental bridge system of FIG. 7.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

A dental bridge system for attaching a natural tooth to a dental implantaccording to a first embodiment of the present invention is illustratedin FIGS. 1 through 4 and generally designated with the numeral 10. Asshown in FIG. 1, natural tooth 12 is embedded in bony tissue 14 via root16. Root 16 is surrounded by periodontal ligament fibers 18 thatflexibly connect root 16 to bony tissue 14. The portion of natural tooth12 exposed above gumline 20 is prepared and shaped to support dentalprosthesis 22 as discussed more fully hereinafter. When natural tooth 12is subjected to forces, such as occlusal forces during biting andchewing, periodontal ligament fibers 18 allow root 16 and natural tooth12 to move slightly within bony tissue 14 in response. This movement canrange from less than 0.25 mm to more than 1 mm.

Dental implant 24 comprises implant anchor 26, exposed portion 28, andimplant crown 30. Implant anchor 26 is surgically inserted into aprepared site in bony tissue 14 of the patient's upper or lower jaw. Asshown in FIG. 1, exposed portion 28 is secured to implant anchor 26 viascrew 32 and remains above gumline 20 after implant anchor 26 is rigidlyfixed in bony tissue 14 through osseointegration. Alternatively, exposedportion 28 may be cemented or otherwise rigidly fixed to anchor 26.Implant anchor 26 functions as an artificial tooth root afterosseointegration is complete. Exposed portion 28 of dental implant 24can support a wide range of dental restoration devices and prostheses.In this embodiment, exposed portion 28 of dental implant 24 supportsimplant crown 30. Implant crown 30 is a cap-like structure that ispermanently fixed over exposed portion 28 of dental implant 24 usingdental cement or any other method known in the art. When in place,implant crown 30 functions like an artificial tooth. Notch 40 forms anopening extending into the body of implant crown 30 through a portion ofthe top and a side of implant crown 30. As shown in FIG. 3, anelastomeric cushion 42 is secured to the inner side and bottom surfaceof notch 40. As shown in FIG. 1, a corresponding notch may be formed inexposed portion 28 of dental implant 24 such that notch 40 in implantcrown 30 may be seated within the notch formed within exposed portion28.

Dental bridge system 10 comprises a dental prosthesis 22 configured toextend between and connect natural tooth 12 to dental implant 24. Inthis embodiment, dental prosthesis 22 comprises natural tooth crown 34,pontic 36, and key 38 extending adjacent one another along a horizontalplane generally parallel to the dental arch of the patient. Naturaltooth crown 34, positioned at one end of dental prosthesis 22, forms acap-like structure that is semi-permanently fixed to natural tooth 12using dental cement or any other method known in the art and coversnatural tooth 12. For purposes of this application, semi-permanent meansaffixed for long-term attachment and not designed for daily removal likedentures are, but could be removed with considerable care and effort forpurposes of repair or adjustment. Pontic 36, positioned between naturaltooth crown 34 and key 38, functions as an artificial tooth. Pontic 36is generally not embedded in bony tissue 14 and sits on or above gumline20, as shown in FIG. 1. While dental prosthesis 22 is shown in thisembodiment to include a single pontic, it should be understood thatmultiple pontics or no pontic may be included within the prosthesiswithout departing from the scope of this invention. Key 38, positionedat the other end of dental prosthesis 22, has a bulbous shoulder 44(shown in FIG. 2) extending outwardly from the upper side edge of pontic36 along the horizontal plane parallel to the dental arch with an arm 46(shown in FIG. 1) extending downwardly along a vertical planeperpendicular to the dental arch. Of course those practicing in the artwill understand that key 38 can have a variety of differentconfigurations without departing from the scope of the presentinvention. For example, key 38 may have a bulbous end and no arm or maybe formed in the shape of a hook or have a t-shaped or flanged end. Inthe embodiment shown in FIG. 4, elastomeric cushion 42 is secured to theexposed side and bottom surface of key 38.

In the embodiment shown in FIGS. 1 through 4, dental prosthesis 22 maybe molded as a single, contiguous, solid piece of dental material suchas dental metal including metal alloys, or a non-metallic dentalmaterial including porcelain, zirconium oxide, or any of the numerousorganic, synthetic, or processed plastic materials that are molded,cast, extruded or drawn into objects. Alternatively, dental prosthesis22 may be formed by securing the individual components to one another byway of soldering or any other method known in the art. Each individualcomponent can be made from the same or different dental materials.

In an alternative embodiment, dental prosthesis 22 may be formed of acore (not shown) covered by a dental material such as porcelain. Thecore provides a structural framework for dental prosthesis 22 and ispreferably made of a suitable material such as a dental metal or can beconstructed of metallic or carbon strands to create a mesh supportstructure. While the entirety of dental prosthesis 22 may be formed of astructural core covered with a dental material, it is also anticipatedthat dental prosthesis 22 may only have a structural core in certainportions, such as to support natural tooth crown 34 or pontic 36. Theremainder of dental prosthesis 22 can be made from the dental materialforming the covering or may be made as separate components secured toone another.

In use, dental prosthesis 22 is semi-permanently secured in place toconnect natural tooth 12 to implant 24 by securing natural tooth crown34 over natural tooth 12 and inserting key 38 into notch 40. In theembodiment shown in FIGS. 1 through 4, the exposed side and bottomsurfaces of key 38 are positioned in abutting engagement with the innerside and bottom surfaces of notch 40 with elastomeric cushion 42positioned at the interface of, and in contact with, these surfaces. Key38 and notch 40 are configured such that key 38 remains seated in notch40 for permanently attaching dental prosthesis 22 to implant 24. Theupper exposed surface of key 38 parallel to the biting surface ofimplant crown 30 may be covered with porcelain or other neutral-coloredmaterial for aesthetic or hygienic reasons.

Elastomeric cushion 42 can be made from any medically acceptableload-absorbing or energy-absorbing material that allows key 38 to moverelative to notch 40 in response to natural tooth movement. The materialfor and shape of elastomeric cushion 42 can vary depending on thedesired range of movement. Elastomeric cushion 42 may be made from acombination of materials and may also have layers or zones of differentmaterials. The materials in the zones or layers of elastomeric cushion42 may have different compression rates or elasticity properties. Oneadvantage of using an elastomeric cushion with zones or layers ofmaterials having distinct properties is the ability to accommodateunusual or abnormal natural tooth movement. For example, if a naturaltooth moves a significant amount in response to occlusal forces,elastomeric cushion 42 might be made of a first layer of materialpositioned in contact with dental implant 24 that is highly elastic andcompressible and a second layer positioned in contact with dentalprosthesis 22 that is less elastic and compressible. This type ofelastomeric cushion could accommodate more initial movement of dentalprosthesis 22 in response to the natural tooth movement but curb themovement as dental prosthesis 22 approaches dental implant 24.Similarly, elastomeric cushion 42 might have a zone of material in acentral core that is stiffer or more elastic than the surroundingmaterial to allow dental prosthesis 22 to mimic the natural toothmovement.

Elastomeric cushion 42 is formed of material to provide a range ofmovement that is anticipated for the specific patient by taking intoconsideration the anticipated range of movement of the natural tooth,and it will preferably provide a range of movement between about 0.1 mmand about 2.5 mm. One skilled in the art could use tools, such as theMiller Index or a paradontometer, to measure and assess the anticipatedrange of movement for the natural tooth when selecting the materials,shape, and size of elastomeric cushion 42. Examples of suitablematerials include but are not limited to rubber, silicone, nylon,polyethylene, copolymers, plastic, Teflon® (commercially available fromDupont E.I. Nemours at 1007 Market Street Wilmington, Del. 19898),compomers, elastomers, santoprene, high density polyethylene,cross-linked polyethylene, polyoxymethelene, other biocompatiblematerials, and combinations thereof.

In the embodiment shown in FIGS. 1, 3, and 4, elastomeric cushion 42 isshaped to fit within notch 40. As shown in FIG. 3, elastomeric cushion42 may be fixed in notch 40 or shaped such that it is held in place innotch 40 by an interference fit (not shown). An example of such aninterference fit may entail notch 40 having a wide gulley and narrowneck and elastomeric cushion 42 having a bulbous end that fits withinthe wide gulley of notch 40 but once in place cannot pass through thenarrow neck of notch 40. Alternatively, elastomeric cushion 42 may becemented to key 38 as shown in FIG. 4. The thickness and overall shapeof elastomeric cushion 42 can vary to accommodate the desired amount ofmovement to be permitted and whether it is being held in place by aninterference fit.

In an alternative embodiment, as shown in FIGS. 5 and 6, system 10 isidentical to that described heretofore with respect to FIGS. 1-4 exceptthat key 38 is configured to be seated in key pocket 48 instead of notch40. Dental implant 24 does not include notch 40, but instead includeskey pocket 48. Key pocket 48 is permanently fixed or formed integrallywith the outer surface of implant crown 30 using dental cement or anyother method known in the art. Like notch 40, key pocket 48 can have avariable depth and width so as to accommodate key 38 and elastomericcushion 42 when system 10 is fully installed. Key pocket 48 can be madefrom dental material such as dental metal including metal alloys, or anon-metallic dental material including porcelain, zirconium oxide, orany of the numerous organic, synthetic, or processed plastic materialsthat are molded, cast, extruded or drawn into objects.

A dental bridge system for attaching a natural tooth to a dental implantaccording to a third embodiment of the present invention is illustratedin FIGS. 7 and 8 and is generally designated with the numeral 110.Similar to the prior embodiments, natural tooth 112 is embedded in bonytissue 114 via root 116. Root 116 is surrounded by periodontal ligamentfibers 118 that flexibly connect root 116 to bony tissue 114. A portionof natural tooth 112 is shaped to support dental prosthesis 120. Dentalimplant 122 is surgically inserted into a prepared site in bony tissue114. As described with respect to the first embodiment above, exposedportion 124 is attached to dental implant 122 and is shaped to supportdental prosthesis 120. In this embodiment, implant crown 126 is formedas a part of dental prosthesis 120, as opposed to dental implant 122.Implant crown 126 is configured to cap or otherwise engage exposedportion 124 of dental implant 122 and elastomeric cushion 128.

As shown in FIGS. 7 and 8, system 110 comprises dental prosthesis 120and elastomeric cushion 128. Dental prosthesis 120 comprises naturaltooth crown 130, pontic 132, and implant crown 126 formed together as anintegral unit. Dental prosthesis 120 may be manufactured in a dentallaboratory and molded as a single piece or may be made of separatecomponents fixed together. In addition, as discussed in relation to thefirst embodiment, dental prosthesis 120 may comprise a structural corecovered by a dental material or may comprise a solid piece of dentalmaterial.

Elastomeric cushion 128 can be formed in the shape of a cap, a donut, ac-shape, a disc, or any other shape that will permit movement betweendental prosthesis 120 and exposed portion 124 of dental implant 122.Elastomeric cushion 128 can be cemented in implant crown 126 or can becemented or otherwise permanently or removably fixed onto exposedportion 124 of dental implant 122. As shown in FIG. 8, elastomericcushion 128 may be positioned such that when it is in place, it isseated in or on a portion of dental implant 122 that forms peripheralchannel or lip 134. Elastomeric cushion 128 can be made from anymedically acceptable load-absorbing or energy-absorbing material thatallows dental prosthesis 120 to move relative to exposed portion 124 ofdental implant 122 in response to natural tooth movement. As heretoforedescribed, the material for elastomeric cushion 128 can vary dependingon the desired range of movement for the individual patient. Elastomericcushion 128 is formed of material to provide a range of movement that isanticipated for the specific patient by taking into consideration theanticipated range of movement of the natural tooth, and it willpreferably provide a range of movement between about 0.1 mm and about2.5 mm. One skilled in the art could use tools, such as the Miller Indexor a paradontometer, to measure and assess the anticipated range ofmovement for natural tooth 112 when selecting the material, shape, andsize of elastomeric cushion 128. Elastomeric cushion 128 may be madefrom a combination of materials and may also have layers or zones ofdifferent materials. Examples of suitable materials include but are notlimited to rubber, silicone, nylon, polyethylene, copolymers, plastic,Teflon®, compomers, elastomers, santoprene, high density polyethylene,cross-linked polyethylene, polyoxymethelene, other biocompatiblematerials, and combinations thereof.

From the foregoing it will be seen that this invention is one welladapted to attain all ends and objectives herein-above set forth,together with the other advantages which are obvious and which areinherent to the invention.

Since many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that allmatters herein set forth or shown in the accompanying drawings are to beinterpreted as illustrative, and not in a limiting sense.

While specific embodiments have been shown and discussed, variousmodifications may of course be made, and the invention is not limited tothe specific forms or arrangement of parts and steps described herein,except insofar as such limitations are included in the following claims.For example, while the elastomeric cushion is shown in direct contactwith the surfaces of the prosthesis and implant components, it isanticipated that the cushion may be positioned in indirect contact withthese components without departing from the scope of the invention.Further, it will be understood that certain features and subcombinationsare of utility and may be employed without reference to other featuresand subcombinations. This is contemplated by and is within the scope ofthe claims.

What is claimed and desired to be secured by Letters Patent is asfollows:
 1. A dental bridge system for connecting a natural tooth to adental implant, said system comprising: a dental prosthesis having atooth crown and an implant crown; and a cap-shaped elastomeric cushionconfigured to be received within said implant crown, wherein saidelastomeric cushion permits said dental prosthesis to move during use ofthe dental bridge system.
 2. The system according to claim 1 whereinsaid elastomeric cushion is fixed to said implant crown.
 3. The systemaccording to claim 1 wherein said elastomeric cushion is configured topermit said dental prosthesis to move in a range between about 0.1 mmand about 2.5 mm.
 4. The system according to claim 1 wherein saidelastomeric cushion is made from a material selected from the groupconsisting of rubber, silicone, nylon, polyethylene, copolymers,plastic, Teflon®, compomers, elastomers, santoprene, high densitypolyethylene, cross-linked polyethylene, and polyoxymethelene.
 5. Thesystem according to claim 1 wherein said elastomeric cushion comprisesmore than one material.
 6. The system according to claim 5 wherein saidelastomeric cushion further comprises zones of said more than onematerial.
 7. The system according to claim 1 wherein said elastomericcushion is configured to permit said dental prosthesis to move at leastabout 0.25 mm.
 8. The system according to claim 1 wherein said dentalprosthesis further comprises at least one pontic formed between saidtooth crown and said implant crown.
 9. A dental bridge systemcomprising: a dental implant having an exposed portion; a dentalprosthesis having a tooth crown configured to cover a natural tooth andhaving an implant crown configured to cover said exposed portion of saiddental implant; and an elastomeric cushion positioned between saidimplant crown and said exposed portion, wherein said elastomeric cushionpermits said implant crown to move relative to said exposed portion. 10.The system according to claim 9, wherein said elastomeric cushion iscap-shaped.
 11. The system according to claim 9, wherein saidelastomeric cushion is fixed to said implant crown.
 12. The systemaccording to claim 9, wherein said elastomeric cushion is fixed to saidexposed portion.
 13. The system according to claim 9 wherein saidelastomeric cushion is configured to permit said implant crown to movein a range between about 0.1 mm and about 2.5 mm.
 14. The systemaccording to claim 9 wherein said elastomeric cushion is made from amaterial selected from the group consisting of rubber, silicone, nylon,polyethylene, copolymers, plastic, Teflon®, compomers, elastomers,santoprene, high density polyethylene, cross-linked polyethylene, andpolyoxymethelene.
 15. The system according to claim 9 wherein saidelastomeric cushion is made from more than one material.
 16. The systemaccording to claim 15 wherein said elastomeric cushion further compriseszones of said more than one material.
 17. The system according to claim9 wherein said elastomeric cushion is configured to permit said implantcrown to move at least about 0.25 mm relative to said exposed portion.18. The system according to claim 9 wherein said dental prosthesisfurther comprises at least one pontic formed between said tooth crownand said implant crown.